The prices of energy sources have increased due to the depletion of fossil fuels, the interest in environmental pollution has been amplified, and the demand for eco-friendly alternative energy sources has become an indispensable factor for the future life. Thus, research into various power generation techniques, such as nuclear power, solar power, wind power, and tidal power, has continuously conducted, and great interests in power storage devices for more effectively using the energy thus generated have also grown.
In particular, with respect to lithium secondary batteries, the demand as an energy source has rapidly increased as the technological development and demand for mobile devices have increased, the use thereof as power sources of electric vehicles (EVs) or hybrid electric vehicles (HEVs) has recently been realized, and the application area has been extended to include uses, such as an auxiliary power source through power grids and the like.
A carbon-based compound that allows reversible intercalation and deintercalation of lithium ions as well as structural and electrical properties being maintained has mainly been used as an anode active material for an anode of a typical lithium secondary battery. However, a significant amount of research into lithium titanium oxides has recently been conducted.
Since lithium titanium oxides are a zero-strain material in which structural changes are extremely low during charging and discharging, lifetime characteristics are relatively excellent, a relatively high voltage range is obtained, and dendrites do not occur. Thus, lithium titanium oxides are known as a material having excellent safety and stability.
However, with respect to the lithium titanium oxides, since electrical conductivities thereof may be lower than those of carbon materials, such as graphite, and atomization may be required to improve charge rates, there may be a limitation that a content of a binder may increase to form an electrode.